Look for fresh blueberries that are firm, dry, plump, smooth-skinned and relatively free from leaves and stems. Size is not an indicator of maturity, but color isóberries should be deep-purple blue to blue-black; reddish berries aren't ripe but may be used in cooking.

Fresh berries should be stored covered in the refrigerator and washed just before using. Use within 10 days of purchase.

Home Freezing BlueberriesWe prefer washing and drying our blueberries prior to freezing, but they may be frozen unwashed and washed just before using. The secret to successful freezing is to use berries that are completely dry before popping them into the freezer. (A ceiling fan or a cool hair dryer may be used to dry berries.) Store in an airtight container or resealable plastic bag. Frozen BlueberriesBlueberries should be kept frozen and the unused portion returned to the freezer promptly. If not used immediately, cover and refrigerate thawed berries and use within three days.

Blueberries may change color when cooked. Acids, such as lemon juice and vinegar, cause the blue pigment in the berries to turn reddish.

Blueberries also contain a yellow pigment which, in an alkaline environment, such as a batter with too much baking soda, may give a greenish-blue color. Blue Batter?

To reduce the amount of color streaking, carefully fold blueberries (right from your freezer, if frozen) into your cake or muffin batter last. For pancakes and waffles, add the blueberries as soon as the batter has been poured on the griddle or waffle iron. This will make the pancakes prettier and they'll be easier to flip. If frozen blueberries are used, cooking time may have to be increased to be sure the berries are heated through.